Process of grinding materials



I06. COMPOSITIONS,

Patented Aug. 22, 1955 COATING OR PLASTIC.

uiTEo STATES PATENT GFFlCE John H. Lundteigen, Detroit, Mich., assignor to The Super'Cement Company, a Corporation of Michigan No Drawing.

Application January 26, 1929 Serial No. 335,392

3 Claims. (Cl.r83=94T' L L My invention relates to a new and useful process of grinding materials and particularly minerals which must be ground to a fine state or pulverized or powdered, such as cement, gypsum plaster, raw materials of cement, pigments, etc.

The process is substantially the same regardless of the material which is to be ground considering the dry grinding operation as distinguished from a wet grinding operation. In the present description, the carrying out of the process may be described in connection particularly with the grinding of cement or the raw materials of cement and this description will be found to be ample for enabling those skilled in the art to carry out the process in the grinding of other materials by a dry grinding process.

In the dry grinding process, it has been experienced that the material being ground has a tendency to cling to the surfaces of the grinding media, and also has a tendency to cohere. This adhesion and cohesion result in a cushioning effect, thus decreasing the efiiciency of the grinding apparatus as well as its capacity. To overcome this adhesion and cohesion is an object of the present invention. It is also an object of the present invention to provide a process whereby material may be ground in the dry grinding process so that a maximum efiiciency of the grinding apparatus may be attained, a greater 30 capacity procured, and a finer grinding of the material made possible.

When the particles of the materialtobe ground, as they are ground, and particularly as the material is reduced to a powdered or pulverized state, can be maintained in a segregated state, the gathering of the material into flakes in the grinding apparatus will be obviated with an overcoming of the disadvantage of such a flaking. A part of the process, therefore, consists in introducing to the material being ground a segregating agent and in this regard the word segregating is used to indicate that the various particles of the ground materials are brought to such a state as to overcome the tendengy to cling together. In addition to overcoming the cohesim the various particles, this segregating agent should also have the attribute of preventing adherence of the ground material to the grinding apparatus.

9 As the material to be ground is fed to the grinding apparatus, and in the grinding of cement, gypsum laster and cement formiir materials tlfis feeding 1S constm ing apparatus with the material to be ground, a segregating agent, this feeding being preferably constant and preferably in a predetermined constant volume or amount. The segregating material is mixed with the material to be ground during the grinding operation. I have found that a very satisfactory segregating material consists MW The term resinous ma eria s 15 use in a sense not determinative of the physical composition or chemical constituents of the material but the word resinous is used in the sense that the adjective is used in classifying dielectric substances.

In the grinding of materials in accordance with this process, I have found that the use of a diffusing material which will serve to readily transmit the segregating agent uniformly throughout the material to be ground is quite desirable and to this end I mix with the material to be ground a diffusing agent. This diffusing agent may consist of any suitable material but I have found that either plaster of Paris or hydraulic cement is most efiicient for the purpose. Although the segregating material may be mixed alone with the material to be ground, I prefer to mix the pulverized resin with a diffusing agent such as laster of Paris or hydraulic cement and then ad To this mixture a su icient quantity of water to set the mixture, after which it may bemred to the material to be ground, either in its formed state or in a crushed condition. The use of the diffusing agent is particularly desirable in cement as it serves to co-mingle the segregating agent with the ground material and form a homogeneous mixture. The use of a diffusing agent such as described, also overcomes any excessive water repellant characteristics of the ground co-mingled materials. It is believed obvious that when a resinous material is to be ground the se regating agent would necessarily be of a vitreg gs nature. Furthermore, by introducing the segregating agent with the diifusing material, in addition to the advantages named, there becomes a uniform diffusion of the segregating agent in the material to be ground at an earlier stage in the grinding process which is a distinct advantage in grinding a material of this kind.

The quantity of the segregating agent to be used as well as the quantity of the diffusing agent will depend upon the nature of the material to be ground and can easily be ascertained by a skilled artisan or engineer working in this trade. In the manufacture of cement, I have found that a mixture of one art of resin five parts of plaster of Paris or hydraulic cemen t forms a desirable and efficient proportion between the difiusing agent and the segregating agent. I have also found that a mixing of one part of the mixture of segregating agent and difiusing agent described with two hundred parts of cement will form a satisfactory mixture for the purposes intended. It will be noted that the materials used are less resistant to abrasion than the material to be ground.

By the use of the process, the material may be ground to a finer consistency and the same volume of production maintained with the same power consumption or the material may be ground to the same consistency with an increased volume production while the same power consumption is maintained.

What I claim is:

1. A process of grinding materials consisting in mixing a segregating agent and a diffusing agent together and delivering the same to the material to be ground during the grinding operation and grinding the whole together.

2. A process of grinding materials consisting in mixing a segregating agent and a difiusing agent together and delivering in a constant delivery the same to the material to be ground during the grinding operation and grinding the whole together. 

